Sedimentation apparatus



E3. E. BUTTON S EDIMEN TAT ION APPARATUS Filed Dec.

me @9 w31,

INVENTOR Berf E/Dui'on "n v Y, A n

Patented Jan. 6, H1931 UNITED STATES PATENT OFFICE BERT E. BUTTON',l OFBOULDER, COLORADO, ASSIGNORr TO THE DORR'COMPANY, OF

lNEW' YORK, N. Y., A CORPORATION OFZDELAWARE SEDIMENTATION APPARATUSApplication led December 21, 1928. Serial No. 327,641.

This invention relates to improvements in sedimentation apparatus of thetype which includes scraping or raking mechanism whose outer end issupported and driven alon the periphery of the tank adapted to impesettled solids to a point of discharge, such as the apparatus shown inUnited States Let- J ters Patent No. 1,356,608.

Apparatus of. this type is designedto move only a certain maximum amountof settled solids having a predetermined resistance to the rakingmechanism; and yit sometimesoccurs that due either to excessive feed,changes in the character of the solids, or changes in the proportion ofsolids in the feed, the set- 1tled solids on the bottom of the tankbuild up to a point where the resistance offeredl to the rakingmechanism is above that for whlch themechanism was designed, eventuallyre' go sulting in'warping or breaking the mechanism.

The, general objectof this inventionl therefore is to provide means forindicating an overload on the raking mechanism which will operate assoon as the overload becomes apprecible and before the danger point 1sreached, especially applicable to the type of \appa ratus shown in thepatent mentioned above, which is often constructed 1n very large sizes,machines as large as 325 feet 1n diameter being in operation. With theselarge machines it is necessary to employ. such large and -heavysupporting and dr1v1ng structures operating in the open under varying-jweather conditions, that ordinary means for indicating overload areunsuitable, cumbersome, unreliable or excessively expensive.

This object is attalned by taklng advantage of the fact that the speedof the outer end of the raking mechanism .along the margin4 of the tankis reduced when the resistance to` the rakes Tises above normal; and ayspeed control device is employed connected to the outer end of theapparatus and travelmg along the tank ledge, with means for operating anindicator, alarm or-other apparatus when the speed of such device fallsbelow a vpredetermined minimum: The device operates generally on thebasls of speed ofrtation caused by its travel along the tank edge, andis adapted to actuate an alarm or the like when its rotational speedfalls below a predetermined point due to the slowing down of and aseries of pockets or the like bordering on the recess which serve tocarry some of the mercury away from the recess when the device rotates,thereby lowering the mercury level below the contact. The mercury drainsback into the recess from the pockets. so that a balance is reached at afixed speed of rotation with the mercury in the recess at a definitelevel, which of course is lowered when the rate of rotation increasesand raised when the rate of rotation is reduced. This characteristic isutilized by setting the contact point at a suitable height Where it willbe out of contact with the mercury when the device rotates at normalspeed; but upon reduction in speed and consequent rise in the mercurylevel the contact will be closed and the alarm operated.

' Further objects are the provision of a small compact device unaffectedby 'weather conditions and which can readily be attached to any type oftraveling apparatus, regardless of the type of drive mechanism, beingparticularly adapted to be attached directly to the drive carriagey ofthickeners of the type set forth in the above patent and to travel alongthe supporting rail thereof.

Other objects and advantages will be apparent from the followingdescription taken in connection with the accompanying drawings in whichFig. 1 is a plan view of the outer or drive end of the raking truss of athickener as described in thelabove mentioned patent, with the alarmdevice attached thereto;

Fig. 2 is a side elevation of said device;

Fig. 3 is a longitudinal vertical section through said device on line3-3 of Fig.` 2,

Patent No. 1,356,608. Motor 33 mounted on the end of truss drives wheel36 resting on rail 31 through suitable gearing suchlas pulleys 40, belts41 a worm on shaft 42,worm gear on shaft 43` and suitable bevel gearconlneotions, not shown,with wheel 36. The precise type of drivemechanism is of course immaterial to this invention. The alarm device isconnected to the outer end of truss 25 so as to roll along the edge oftank 2, andpreferably on rail 31. In the form illustrated the alarmdevice indicated generally at 44 is mounted on an arm 45 pivotallyconnected at 45a to the truss 25 to permit the alarm device to followthe rail 31. The alarm'device 44 comprises in general l a body 46 in thegeneral shape of a wheel preferably provided .with flanges 47 to keep iton the rail 31. 'lhe wheel body 46 is mounted on a tubular stub shaft 48carried in a bore in the offset end of arm 45 and adjustably clampedtherein by set screw 49. A suitable bushing 5() butting againstretaining shoulder 51 on stub shaft 48, with packing ring 52 of felt orthe like, grease cup 53 and grease channel 54 may be included.

The outer face of body 46 is formed with an annular series of pockets 55communicatingthrough passages 56 with a central recess 57 vadapted tocontain mercury or other fluid conductor of electricity. A contactmember 58 is located in recess 57 and is insulated from the body 46 andother parts of the alarm device 44 as by means of insulation vblocks 59and 60. In'theform illustrated the block 59 is in the form of a disc setinto the end of the stub sha-ft 48,' and held in place by connectingbolt 61 whose head is insetin a recess'62 in the disc face and whichbears at the `other end against block resting against a suitableshoulder 63 in shaft 48. The contactA memberl 58 may lbe'in the form: ofa illister headed bolt passing radially through theirisulationdisc 59and thread-- ed into the head of bolt 61, the head of the member-58being-.counter-sunk flush with the surface of disc 59.. y

Pockets 55 and recess 57 are suitably closed as by a removable coverplate 64 held'l bolts 65 and having a central opening 1n register withtheheaddof bolt 61 and closed by athreaded plug 70. Disc 59 ispreferably proportioned to have only a lslightkslearance .from the boly46 and cover plate-64 to form aarestrictedf pocket; and-passages 56 mayface of the body 46 around pockets 55 to 'A prevent passage of theconducting Huid to and from the pockets ,except through passages 56 and66. l

The contact member 58 is connected to one terminalof a suitable sourceof electricity B as by means of the insulated cable 67 connected to theend of bolt 61 and passing through conduit 68 set into the projectingend of the hollow stub 48. The mercuryl or other conducting fluid incentral recess 57 is arranged for electrical connection with the otherterminal, as by connecting said terminal to therail 31 on which thewheel 48 rests, with.- a suitable device or signal such as the alarmbell 69 in circuit.

In operation mercury is introduced into the central recess 57 and fillsthe lower pockets 55 and said recess up to a predetermined levelsubstantially below the center of theA alarm device. The head'of thecontact member 58 is then adJusted to a suitable height, as by removingthe plug 7 and rotating disc 59 and bolt 61. The head of contact member58 is shifted in the direction in which thealarm device 44 will travel,but is positioned substantially below the level of the mercury in recess57 when the device is at rest.

` vWhen the thickener is started up and truss l25 begins to travelyalong rail 31, the wheel ,body 46 is rotated as it rolls alongthe`rail. This rotation lifts the pockets 55 containing mercury at the`rear of the Wheel and deesses those toward the front of the wheel, Viththe resultant lowering in the mercury l'evel toward the front of thewheel to aupoint where the level is below the end ofthe contact member58. The mercury will drain from .the elevated pockets at the rear of theWheel through passages 56 into the rear. portion of recess 57, andthrough passages 66 into subjalob uur)

lio

cent pockets 55; while the pockets 55 Which are brought below themercury level at the front of the wheel 46 by its rotation are lled withmercury from recess 57 through passages 56, and' likewise to a certainextent by lateral flow through passages 66 from adjacent pockets,Passages 56 and 66 are designed so asl to restrict the rate of mercury(discharge from the pockets 55 to the extent necessary to maintain a lowmercury level at the -forward' side of'recess 57 when the wheel 48 isrotating at normal speed, without carry- Y ing the mercury up over thetop of the wheel at that rate of rotation. y With this arrangement themercury level in recess '57 at the forward side of the wheel e adjacentthe contact member 58 will be maintamed at an elevation determined bythe speed of rotation of the wheel 46, since more rapid rotation will-cause the pockets 55to carry more mercury upwardly on the ascendingside of the wheel; whilel slower speed of rotation will afford more timefor-the mercury to flow back into the recess 57 thereby raising thelevel therein. Consequently the level of the lnercury in recess 57 atthe forward side will be in general proportional tol the speed ofrotation of the wheelfl within 'the limits defined by the size of thepassages 56 and 66 through which the mercury drains back into recess 57.

Asthe speed of rotation of the wheel 46 is directly proportional to therate of travelof truss 25, the level of mercury in recess 57 will remainat a predetermined point when the truss is traveling at normal speed. Ifhowever, the Atruss for any 4reason should travel more slowly thannormal, or should stop, the level of mercury in recess 57 will at oncerise; ^and :the device is very sensitive to slight changes in rate ofrotation. The head of contact member 58 is therefore set slightly abovethe mercury level in recess 57 when the truss 25 is travelingr at normalspeed, but below the mercury level in said recess when the truss isrunning at a lower speed. When the mercury level rises to a point wherea contact is made 3o with the member 58 the electrical circuit is closedand the alarm 69- or other electricaly device is actuated, giving timelywarning of the diliiculty which has caused the truss 25 to slow down. Bysuitable adjustment of con- I tact member 58the precise slower speed atwhich the electrical circuit will be established can be regulated withgreat accuracy.

It will be apparent that a number of other arrangements, electrical andotherwise, may

be employedifor the same purpose within the scope of thisr invention.However, the arrangement disclosed is compact, simple, com-VL pletelyprotected against weather conditions, and by using mercury is free frompitting and other difficulties encountered normally when opening andclosing electrical circuits, especially when relatively slow contactsare made or` broken. The device 'is likewise adapted for use on machinesin which the outer end of the truss 25 or its equivalent follows a.non-circular path.7

While an alarm device is shown as being adapted to travel on thetraction surface of the sedimentation tank, it is to be distinctlyunderstood that departures from such an arran-gement are contemplated.For example,

the device may have engagement with a separate traction surface eitherwithin or without the wall of thesedimentation tank. r

I claim:

1. A tractionally driven sedimentation apparatus comprising a scrapingdevice `adapted to travel over the bottom of a sedimentation tank toimpel settled lsolids to a discharge, and `means operable by engagementwith the traction surface of the sedimentation apparatus, and responsiveto variations in the rate of travel of said device, for producing apredetermined action corresponding to a selected variation in the rateof travel.

2. The combination with a tractionally driven sedimentation apparatuscomprisin a scraping device adapted to travel over t e bottom of asedimentation tank to impel set'- tled solids to a discharge, of meansoperable by engagement with a traction surface and responsive tovariations in the rate of travel of saiddevice for producing apredetermined action correspondmg to a selected variation in the rate oftravel.

3. kThe combination with a tractionally driven sedimentation apparatuscomprising 'y f a scraping device adapted to travel over the bottom of asedimentation tank to impel settled solids to a discharge, of electricalmeans cooperating with a traction surface and responsive to variationsin the rate of travel of'said device for producing a predeterminedelectrical action corresponding to a selected variation in the rate oftravel.

4. The combination with the wall of a sedi.

mentation tank of a sedimentation apparatus comprising a scraping deviceadapted to travel over the bottom of a sedimentation tank to impelsettled solids to a discharge, of means traveling with said device andengaging the said wall to be actuated thereby for producing apredetermined action corresponding to a selected variation in the rateof travel.

5. The combination with the tank of a sedimentation apparatus comprisinga scraping device adapted to travel over the bottom of the sedimentationtank to impel settled solids to a discharge, of means traveling with thedevice and maintained in rolling engagement with the tank to be actuatedby said engagement for producing a predetermined action corresponding toa selectedvariation in the rate of travel.

6. The combination with a margin of a sedlmentation tank of asedimentation apparatus, comprising a travelin scraping device forimpelling settled soli s to a discharge and having an end supported onand adapted to travel along said margin, of means operatively associatedwith said end and maintained in rolling contact with the margin of 1 thetank for producing a predetermined action responsive to a selectedvariationl in the rate of travel.

7. The combi/nation with the margin of a a separate circuit andoperatively associated with said end and traveling therewith forproducing a predetermined action responsive to variatlons in the rateof'travel of said device. .p

8. The combination with'a sedimentation tank of :a sedimentationapparatus comprising a scraping device adapted to travel over the bottomof the tank to impel settled solids to a discharge, of a wheel mountedon and traveling with said device and maintained in rolling contact withthe tank, and means responsive tovariations in the rate of rotation ofthe wheel for producing a predetermined action responsive to a selectedvariation in the rate of travel.

9. The combination with the Wall of a sedimentation tank ofasedimentation apparatus comprising a traveling scraping device forimpelling solids to a discharge, of means cooperating with the wall forclosing an electrical^ circuitwhen the rate of travel of the scrapingdevice is less than the prede- Vtermined minimum rate, said meansinclud- -`level, electrically actuated means for producing apredetermined action and an electrical circuit for connecting the liquidand said terminal with said means to actuate the latter when the liquidand the terminal make contact to close the circuit..

10. The combination with the wall of a sedimentation'tank of asedimentation apparatus comprising a travelingscraping device forimpelling solids to a discharge, of means cooperating with the Wall forclosing an electrical circuit when the rate of travel is less than thepredetermined minimum rate, said means including a casing adapted to`travel on the Wall, a reservoir 1n the casing, an electric conductingliquid'in Vthe casing, a terminal positioned for contact with the liquidwhen the liquid reaches a. predetermined level, and means for varyingthe level of the liquid in said reservoir in accordance with variationsin the rate of rotation of the casing. i

11. The combination with a traction surface of a sedimentation apparatuscom rising a traveling scraping devlce for impe ling settled solids to adlscharge, of means on the traction surface for closing an electricalcircuit when the rat-e of. travel is less than av predetermined minimumrate, said means including a casing adapted to travel on the tractionsurface, a reservoir in the casing, an electric conducting liquid inthereservoir, an insulated terminal positioned for contact with the liquidwhen. the liquid reaches: a predetermined level, and.' means for with-'rawing portions of said liquid from the resyervoir during rotation ofthe' casing and returning said liquid to the resrvoir at a ratedetermined by the rate of rotation.

12. The combination -with a .traction Surface of a tractionallydrivensedimentation apparatus comprising a scraping device for impellingsettled solids to a discharge, of means on the traction surface forclosing an electrical circuit when Ythe rate of travel is less vthan apredetermined vminimum rate, said means including a casing adapted totravel on the traction surface, a reservoir in the casing for anelectric conducting liquid, an insulated terminal positioned for'contactcWith the liquid when the liquid reaches a predetermined level, saidcasing including an annular series of recesses communicating with thereservoir adapted to withdraw liquid from the reservoir to reduce theliquid level therein during rotation and provided with draining outletsfor returning the liquid to the reservoir.

13. The combination with a traction surface of a tractionally drivensedimentation apparatus comprising a traveling scraping n0 device, of acasing operatively associated with the traction surface and adapted toroll on the lsame at a rate corresponding to the rate of travel of thedevice, said casing including a reservoir for electric conductingliquid, and an annular series of recesses extending around the reservoirand communieating therewith through restricted openings adapted toWithdraw liquid from the resl ervoir during rotation of the casingtogether n,

to the reservoir through said openings, the

construction and arrangement being such. that the level of liquid in thereservoir will m5 have a predetermined relationship to` the f speed ofrotation inJthe casing; and an insulated tContact member eXte'ndin intothe reservoir and adapted to make e ectrical contact with said liquidwhen the liquid reaches im a predetermined point.

14. The combination with atraction surface of a tractionally drivensedimentation apparatus comprising a traveling scraping device, of acasing operatively associated with |15 the traction surface and adaptedtojroll therealong at a rate corresponding to the rate of travel of thedevice, Vsaid casing including a reservoir for electrically conductingliquid,` an annular series of recesses extending around the reservoirand communicatinorw therewith throu h restricted openings, and adaptedto with rawy liquid from the reservoir during rotationof the casingtogether with the series of recesses around the reSer-1'25 voir and toreturn the withdrawn liquid tothe lreservoir through Said openings, thecon-

